rh.html

Clarification of Rh Factor Risk in Health Care Workers

by Dr. Janine Jagger

The San Francisco Chronicle recently did a very extensive 3-day series
on needlestick injuries. I provided a lot of information to one of the
reporters. When the article was published on April 13-15 it was
sensationalistic in tone and contained a great deal of misinformation.
Unfortunately, this applied to an issue that was raised during my
interview. Because this article is getting into more widespread
distribution, I wanted to provide you with the facts in order to avoid
confusion if questions about this are raised in your institution. The
following paragraphs include my statement to the organization of
Occupational and Environmental Medicine.

I was alarmed when I read the article about Rh factor risk in health
care workers published in the San Francisco Chronicle on April 13,
1998. I am concerned that my statements have been incorrectly construed
and presented by the reporter as exaggerated claims.

During an all-day interview, primarily dealing with other health care
worker safety issues, I told the reporter that I was looking into the
question of whether Rh immunization could occur after occupational
blood exposures since there is no documentary evidence that this
question has been considered in relation to occupational blood
exposures. The reporter asked me some general questions about the Rh
factor and the consequences of Rh immunization. When I saw the article
I was shocked at how my comments had been transformed. The reporter
treated this information as a "scoop" and turned it into a
sensationalized piece. The article refers to a "discovery." There is no
discovery, only questions. The article refers to my "research" on this
subject. There is no research, only a literature review and
conversations with colleagues. The article refers to thousands of
health care workers who might be unknowingly affected and their fetuses
threatened. I do not know of any case in which this has occurred. The
article also outlines post-exposure treatment parameters which I would
never presume to propose to my medical colleagues. If the facts had
been accurately stated, there would not have been much of a story left
to write.

I have raised the Rh issue as a theoretical question, and it remains an
interesting question. Several cases of Rh immunization have been
reported in needle-sharing, intravenous drug users. It should be noted
that the circumstances are not necessarily similar to those of
occupational needlestick injuries. Consequently, I have been looking
into whether there are theoretical parameters under which Rh
immunization could be an occupational risk. Based on experimental work
done in the early 70's which quantifies volume of blood in an exposure
and percentage of Rh negative cases developing antibodies, the risk of
Rh immunization may be present in unusual cases when HCWs are
accidentally injected with blood (a few such cases of injection have
been described in HIV-infected HCWs) provided the HCW is Rh-negative
and the source is Rh-positive. In reviewing the circumstances of those
HIV+ cases, blood injection is most likely to occur when blood has been
drawn into syringes, since blood can be injected out of a syringe, but
not out of a vacuum tube. One cc of blood is well within the range that
could cause Rh immunization. However, the amount of blood that could be
contained within the bore of a blood drawing needle (in cases in which
injection does not occur) is much less than the amounts that have been
experimentally tested. The experiments did not define a threshold below
which sensitization cannot occur. This is as much information as my
inquiries have yielded to date.

I do think this question bears investigation. Testing a series of
blood-exposed health care workers either prospectively or in a
look-back study would determine whether a theoretical risk translates
into a real risk. I am hoping that the SF Chronicle piece does not
result in alarm among health care workers or frightened calls to
occupational health personnel. And I hope this explanation puts the
issue into a more realistic perspective.

There were other aspects of the 3-part series of articles that were
sensationalized. I think the whole series should be taken with a grain
of salt. However, after the dust settles, perhaps the attention drawn
to the issue of health care workers’ risks will be a good thing
overall.

Postscript: Please note that the above clarification does not include
any suggestion regarding changes in post-exposure protocols. My
investigation to date has involved information gathering only and
should not be construed as any kind of recommendation. JJ